Cellulosic biomass is a significant renewable resource for the generation of fermentable sugars. These sugars can be used as substrates for fermentation and other metabolic processes to produce biofuels, chemical compounds and other commercially valuable end-products. While the fermentation of sugars such as glucose to ethanol is relatively straightforward, efficient conversion of cellulosic biomass to fermentable sugars is challenging. Ladisch et al., 1983, Enzyme Microb. Technol. 5:82.
The conversion of cellulosic biomass to fermentable sugars may begin with chemical, mechanical, enzymatic or other pretreatments to increase the susceptibility of cellulose to hydrolysis. Such pretreatment may be followed by the enzymatic conversion of cellulose to cellobiose, cello-oligosaccharides, glucose, and other sugars and sugar polymers, using enzymes that break down cellulose. These enzymes are collectively referred to as “cellulases” and include endoglucanases, β-glucosidases and cellobiohydrolases.